If you're a layperson try "Tripping over the Truth" by Travis Christofferson. If you have some biology try "Cancer as a Metabolic Disease" by Seyfried.
Damage to DNA and mitochondria is happening all the time, the question is what happens in the presence of high carbohydrate loads. If you read the books they'd tell you this.
How about cell cultures that are induced with viral vectors to become cancerous by the introduction of an oncogene? Do you think there is a difference in metabolism in the cells that become tumorigenic after transfection? If so why does it happen with introduction of an oncogene but not in the control vector when they have identical cell culture media/nutrients?
My bet is because more than one thing happens (some insult to the mitochondria in parallel, say) and/or because the gene is actually expressing something metabolic we don't understand. Seyfried (I think) actually points out the parallel metabolic influence of some therapies that we think are working genetically.
So if the gene, which is DNA, is expressing something that changes the metabolism, doesn’t that mean a change in DNA is ultimately responsible?
Edit: also if you could introduce a change in the cells that only changed the metabolism and didn’t alter DNA you could prove your theorem if you then caused them to be tumorigenic.